This country lacks a cohesive, informative surveillance system for vascular disease that can provide insights into national patterns of cerebrovascular disease and reveal national trends over time. Our overall goal is to build a surveillance system for the majority of patients admitted to the hospital with stroke in the United States, patients age > 65 years who are enrolled in the Medicare fee-for-service (FFS) option. We have assembled an unprecedented national resource by creating a longitudinal Medicare database for patients hospitalized with vascular diagnoses over the years 1992-1999, with ability to add years (through 2003 as part of this project). Since our original submission, our team has overcome considerable technical difficulties to create this database. This work has entailed transforming more than 5,000 data tapes into a viable data resource containing more than a terabyte of data. Previous studies using Medicare databases have employed a cross-sectional approach, not linking, at the patient level, the entire Medicare Part A (hospital admissions) database over time. No other organization or institution, not even the Centers for Medicare & Medicaid Services (CMS), has developed such a database. Our objective is to provide the most comprehensive evaluation of stroke and short-term mortality outcomes among hospitalized Medicare FFS beneficiaries in the United States. The evaluation will encompass the entire United States and span more than a decade. Accordingly, we propose the following specific aims: 1. To determine rates of stroke hospitalizations among Medicare beneficiaries in the United States. 2. To determine rates of hospital and 30-day mortality following stroke hospitalization among Medicare beneficiaries in the United States. 3. To determine patterns of stroke hospitalization among subgroups including by age, race and ethnicity, and by economic, political, and geographic characteristics. 4. To measure trends in stroke hospitalization rates over time Our work will help better define the burden of stroke among the elderly, inform policy-makers and clinicians in planning for the health care needs of stroke patients, and help identify targets for interventions to enhance the care of patients with stroke.